Generally, grooming and cosmetic treatments of hair by washing, brushing, heating with dryers, permanent-waving, hairdyeing or the like, substantially deteriorate and weaken the hair, and destroy the structure of the surface of the hair. Consequently, the hair dries and becomes brittle, split ends are formed or the hair may break, and lose its strength, while hair constituent proteins are eluted by treatments with shampoos, perm chemicals, hair dyes or the like and thus the proteins gradually disappear. Thus, with the elution of the proteins, the hair is made thinner and the likelihood of damage increases. The hair, once damaged, is unable to restore itself to its original state. Therefore, it is necessary to protect the hair from damage and in case of damage, to repair the damaged hair, in order to keep the hair beautiful and healthy.
For this purpose, hydrolysates of various proteins of natural origin or derivatives thereof have been used heretofore as a hair protective ingredient in hair care products such as shampoos, rinses, treating agents and the like. However, these substances have drawbacks such that they are readily washed away with water due to an extremely poor compatibility with hair, particularly because of their high water solubility, so that they have not been sufficiently effective.
On the other hand, U.S. Pat. No. 3,987,161 discloses a method for imparting improved body and set retention to the hair, using an antiserum which is prepared by using hair particles per se as an antigen. However, the antiserum prepared by this method binds to hair proteins so weakly that it has not been satisfactorily effective in preventing the elution of proteins from the hair or repairing the damaged hair.
Incidentally, hair consists of 3 types of cells: an outer cuticle wrapping and protecting the hair fiber, a cortex, i.e. the hair fiber itself, and a central medulla (hair medulla).
Among them, the cortex is composed mainly of three different types of proteins: fibrous "keratins which constitute filaments" (or .alpha.-keratinous fibrous proteins), non-fibrous "matrix proteins" and cell membrane peripheral proteins.
It has been known that the keratins which constitute intermediate filaments also exist in epidermis, nails, down, etc. are insoluble in water and solubilized in the presence of a denaturing agent, such as urea, SDS or the like, or a reducing agent, or by means of a chemical modification or the like. These proteins which originate from hair contain plenty of cystine and proline but little glycine, while those of an epidermis origin contain plenty of glycine and serine.
In the present invention, keratins which constitute intermediate filaments, which are obtained by solubilizing hair (nails or the like) under severe conditions as described above are employed, other than mere hair particles as described in the aforementioned U.S. Pat. No. 3,987,161.
It is known that an antibody to the keratins which constitute intermediate filaments is produced in the serum of animals such as rabbits, mice, guinea pigs or the like or in a culture solution of spleen cells of such animal origin (Baden: J. Jnvest. Dermatol., 75., 311, 1980; Cotton: Br. J. Dermatol., 3, 63, 1984; T. Tazawa: J. Jpn. Dermatol., 95, 157, 1985; Heid: Differentiation, 32, 101, 1986; etc.). However, it has been shown that these antibodies of mouse or guinea pig origin also react with cytokeratin of epidermal origin to histologically stain tissues of epidermal origin. Thus, it is assumed that the resulting antibodies also react on other epidermal portions such as scalps or the like. With respect to the antibodies of rabbit origin, they are difficult to react with skin but do bind to hair. In the above case, however, the hair is incompletely keratinized, because parts, such as follicles and roots, are soft tissue, and the reactivity of this antibody to completely keratinized hair shafts, to which the present invention is directed, is not discussed. It has been a general idea that antibodies do not bind to keratinized portions, as Tazawa (as referred above) and French et al. (J. Cell. Biol., 102, 1412, 1986) have discussed on monoclonal antibodies.
Further, it has been well demonstrated that a female bovid animal is an effective factory for generating antibodies, and generates a serum containing antibodies to antigens that have been injected into her, and in addition generates milk containing the same antibodies as the serum. However, the reactivity to skin or hair of antibodies manufactured by using, as an antigen, keratins which constitute intermediate filaments has been totally unknown.